A new maintenance release of IGraph/M is now available. This is a bugfix release recommended for all users. As usual, the simplest way to upgrade is to evaluate the following, and then restart Mathematica:
Get["https://raw.githubusercontent.com/szhorvat/IGraphM/master/IGInstaller.m"]
IGraph/M 0.6.3
Changed:
 When an invalid vertex is passed to IGraph/M functions, now the message shown is
IGraphM::invv
instead ofVertexIndex::inv
.
Fixed:
 In rare cases, vertex names that were lists of other vertex names in the same graph were misinterpreted. This affected only Mathematica 12.0 and later.

IGCommunitiesLeadingEigenvector
is less likely to fail to converge now. 
IGCommunitiesLeadingEigenvector
now respects random seeds set in Mathematica. These affect only the random starting vector it uses internally, which can very rarely cause nondeterministic output. 
IGBarabasiAlbertGame
no longer accepts negative or zero exponents, as these were not handled correctly. 
IGBridges
is no longer prone to stack overflow when given very large graphs.
Other:
 Performance improvements for
IGGraphEditor
.  Documentation improvements.